Should I Be Concerned About Cold And Diarrhea In A Toddler When Stool Smells Like Burning Hair?

Hi, I have a 2-year-old that s been sick off and on for the past week, the doctor said nothing to worry about just a cold, he s been having diarrhea with it also. But this time when he went it smelt like burning hair, still diarrhea, and the smell was so bad, he didn t seem to be in any pain or anything. There s been no diet change and no new medications. Should I be worried